this is singapore's central business district, the poor sink -- pulsing heart of singapore's economy, but today, you see the building stranded and smoke. there is a dry, accurate taste in the air. you can feel it in the back of your throat. -- there's a dry, accurate -- there's a dry, acrid taste in the air. his is where the fumes are coming from. hotspots on the indonesian island of sumatra where farmers use/and burn techniques to clear the land -- use slash and burn techniques to clear the land. >> ideally, we would like the fires to be put out. if any of these fires were illegally started, then whoever is responsible for them to be brought to justice. for the long term, what we need to do is cooperate with the indonesians as we have been to work on developing sustainable agricultural practices. >> the cost of the smog is yet to be counted, but it could be in the billions. had economichaze costs estimated at more than $9 billion and reportedly made 20 million people ill across the region. looks ugly there in singapore. you are watching "bbc world news america." still to come -- what